I have had one for the last 20 years. It is a rebarreled Ruger 77, that was a 7 mag. The 358 Norma is not complicated to deal with. 338 Win Mag brass necked up and fireformed with cheap 357 pistol bullets work fine. The case is a little short, but after a couple of full power handloads, the case length is just fine. I have used 180-225gr bullets. Powders I have used are 4064, 4895, and 4350. Of course the 4350 is with the 225 gr bullets. Get a chronograph and work up watching for pressure signs. You will find most 358 Norma data on the mild side. I starting using an old Speer Manual and the data there was on the hot side for my gun.
I would suggest rebarreling like I did. I think this would be the best bang for the buck. My gun is very accurate. It shoots 180 gr pistol bullets real well at 100yds. I have used my gun for nilgai, bear, caribou, elk, and deer. Love mine.